Pulper impeller vane



March 11, 1969 c. A. JOHNSON PULPER IMPELLER VANE Filed Dec. 22, 1966INVENTOR. Charles A. Johnson BY PW v-P ATTORNEYS United States PatentOfice 3,432,107. Patented Mar. 11, 1969 6 Claims This invention relatesto a novel and improved disintegrator or pulper of the type used in thepaper industry. More particularly, the invention relates to a novelpulping impeller and to novel pulping vanes for mounting thereon.

The type of pulper to which the invention relates may be either aside-rotor pulper or a bottom-rotor pulper a single rotor pulper or adual rotor pulper.

It has heretofore been proposed, as in US. Patent No. 2,999,650, toCampagnano of Sept. 12, 1961, to provide a composite impeller in whichthere are a set of curved vanes for creating the usual vorticalcirculation in the tank, and a second set of spoon shaped blades havingupturned terminal tips for creating a secondary vortical circulation. InUS. Patent No. 2,996,313 to Hughes of Dec. 27, 1960, two sets of bladesare also disclosed, each on a separate impeller, and each havingtriangularly upturned terminal tips for chewing up the stock. While theuse of an abruptly upturned terminal tip on the vanes, disclosed inthese patents, may well be useful for attrition purposes as in Hughes,or for creating a multple vortical circulation pattern, as inCampagnano, such a configuration does not solve, the problem of theplugging, matting or stapling ofmaterial on the vanes. It has been foundthat in all circulating vane structures presently used in waste paper,or broke, pulpers, despite the vortical circulation created by theimpeller, the pulper gradually loses efliciency, due to an accumulationof material, especially on the leading edge of the vanes.

Applicants have discovered that a very substantial improvement in fiberstock handling characteristics of a pulper may be achieved byutilization of a pulping impeller comprising a plurality of identical,curved pulping vanes, which include, centrally of their length, anabrupt upward curvature to form an inwardly-facing surface or wall,thereby forming a flow barrier and a zone of turbulence in the outwardlymoving stream of stock. This novel design has been found to facilitatethe handling of diflicult-to-handle stock including paper waste, and tovirtually eliminate plugging and stapling problems over a very widerange of pulping operations. Moreover, when these inwardly-facing walls,or surfaces, which are preferably nearly normal to the plane in whichthe pulping impeller is operating, are somewhat remote from the impellercircumference, for example, set back at least 20% of the distance fromthe periphery to the hub of the impeller, an especially beneficialcirculating pattern featuring a relatively small vortex of less diameterthan the impeller diameter is acheived.

Accordingly, it is an object of the invention to provide a novel pulpingapparatus which contributes efiicient and continuous trouble-freeoperation to pulping operations.

It is another object of the invention to provide a pulp ing impellerwhich resists plugging, matting or stapling on the impeller vanes.

Another object of the invention is to provide an apparatus for creatingsulficient turbulence intermediate of the impeller to lift off adheredmaterial on the vanes without unduly interfering with the normalvortical flow path of the pulper.

Other objects of the invention will be obvious from the claims thedescription of the drawings, and from the drawings.

In this application and accompanying drawings, a preferred embodiment ofthe invention has been shown and described and alternatives andmodifications thereof have been suggested, but it is to be understoodthat these are not intended to be exhaustive and that other changes andmodifications can be made within the scope of the invention. Thesesuggestions herein are selected and included for purposes ofillustration in order that others skilled in the art will more fullyunderstand the invention and the principles thereof and will be enabledto modify it and embody it in variety of forms, each as may be bestsuited to the condition of a particular case.

FIGURE 1 is a sectional view in elevation of a pulper in which ismounted a pulper impeller according to the invention.

FIGURE 2 is a plan view on line 2-2 FIGURE 1.

FIGURE 3 is a perspective showing part of a pulper rotor of theinvention with the novel pulping vane mounted thereon.

FIGURE 4 is a view in elevation of a pulper vane according to theinvention.

Referring to FIGURE 1, it is seen that the pulp disintegrator, orpulper, 20, has a pulp container 21 with a fiat, horizontal, centralbottom portion 22, an upwardly sloping outer bottom portion 19, and anupstanding cylindrical wall 23. The pulp container 21 is adapted toreceive a charge of water and paper stock material such as broke paper,waste paper, virgin lap pulp or the like. An arcuate sump 24 extendsaround the outer periphery of the container with a screen 25 in thebottom 22 and a drain pipe 26 all in a manner well known to the art fordischarging the pulped stock. Impeller 30 is mounted in container 21just above the bottom 22 to rotate in a horizontal plane on a verticalaxis by means of central drive shaft 32. Drive shaft 32 is suitablyjournalled in bearings 34 mounted in bearing housing 35 fixed belowcentral bottom aperture 36 of container 21. Commercially availableO-rings and closure seals are used to prevent leakage in a manner knownto the art and unnecessary for description in detail herein.

Impeller 30 includes a plurality of identical blades or pulping vanes37, each of predetermined length, and having opposite and substantiallyparallel side faces 39 and 40. Vanes 37 are spaced on the flatdiametrical face 27 of backplate 38 of impeller 30. Each vane 37comprises an arcuate inner portion 41 which merges with a substantiallystraight outer portion 42. Arcuate portion 41 rises from proximate thecentral portion of backplate 38 to a first position centrally of thelength of the vane and at about a constant 19 angle. Straight portion42, however, starting approximately at the said first position at thejuncture of portions 41, 42, rises sharply in rate of angular departurefrom backplate 38 to form an upwardly curved face which terminates in avertical wall, or edge face, 43, substantially normal to backplate 38 ofimpeller 30 and facing inward toward the center of the impeller at asecond position centrally of the length of the vane. The upper edge face44, of straight portion 42, is substantially parallel to backplate 38 ofimpeller 30 and vane 37 terminates in a downwardly sloping face 46,which extends beyond the edge of backplate 38.

Impeller 30 may include, along the outer periphery thereof, a series ofprojecting attrition blades 47, spaced around the periphery of theimpeller and each at a predetermined angle from a radial line throughthe blade.

In operation, water and waste paper are supplied to container 21 andimpeller 30 is caused to rotate by shaft 32. Pulping vanes 37 provide arecirculating action while attrition members 47 provide a shreddingaction on the waste paper pulp.

Whether the pulper is a side drive or bottom drive type, the vanes 37create the usual vortex in which the material is continually movedaround the side walls, or up the side Walls, and is then drawndownwardly along the axis of the rotor impeller toward the centre and isthen again centrifugally thrown outwardly toward the side walls. Thisconventional, and Well known, vortical circulation is showndiagrammatically by the hollow headed arrows and continues unchanged inthe pulper of this invention, and is called the closed, vorticalcirculation path.

The dislodging action of the pulping vanes 37 of this invention is of aparticularly advantageous nature in that a cylindrical zone ofturbulence 49 appears to be formed, of less diameter than that of theclosed vortical circulation path. The zone of turbulence is defined bythe vertical walls 43 of the rotating vanes 37 which are believed tocreate a lifting force along the vanes capable of dislodging upwardly orforwardly any material tending to adhere to the leading edges of theblades. In FIGURE 4, the zone of turbulence 49 is shown diagrammaticallywith solid headed arrows. Stapling, matting and plugging are thusprevented, perhaps also because of the steep accelerating action of therapidly rotating vertical walls 43 which imparts a high upward velocityto material coming in contact therewith. In a typical pulping operationthe impeller will rotate at 400 to 500 r.p.m. At about 490 rpm. the tipwould travel about 4,000 feet per minute. At such speeds some types ofwaste paper, for example a piece of a paper pie plate, may tend to hangup on the leading upper edge 50 of the upper face of one of the pulpingvanes 37. This hanging up, or stapling, as it is known to the art, doesnot occur with the pulping vanes 37, the vertical walls 43, rotatingunidirectionally at high speed, constituting identical barriersintermittently moving into and out of the flow path, intermediate of thevanes, to remove any material which might tend to adhere to the vanes.

Although a particular embodiment of the invention has been disclosedabove in detail for illustrative purposes, it will be understood thatvariations or modifications of such disclosure, which lie within thescope of the appended claims are fully contemplated.

What is claimed is:

1. A pulper impeller of the type rotatable by a shaft within a tank forpulping fibrous paper stock material, said impeller comprising:

a backplate, mounted fast on said shaft and having a flat, diametricalface in a single plane normal to the axis of said shaft,

and a plurality of pulping circulation vanes, uniformly spaced around,and projecting axially from, said backplate,

each said vane being substantially arcuate in plan, being ofpredetermined length, and being of substantially uniformly increasingheight from a position proximate the central portion of said backplateoutwardly to a first position centrally of the length of said vane,

said vane increasing abruptly and substantially in angle of slope fromsaid first position centrally of said length to a second positioncentrally of said length to form an inwardly facing wall substantiallynormal to the plane of said backplate and parallel to the axis of saidshaft,

whereby the said inwardly facing walls on said vanes form a rotatingbarrier to outward vortical flow from said impeller, the resultingturbulent zone preventing plugging, matting, and stapling of material onsaid vanes.

2. A pulper impeller as defined in claim 1:

wherein each said vane includes parallel, opposite side faces ofsubstantially constant increasing height from said position proximatethe central portion of said backplate outwardly to said first positioncentrally of the length of said vane and includes a uniformly sloped,planar, outer edge,

said outer edge abruptly and substantially increasing in angle of slopefrom said first position to a second position centrally of the length ofsaid vane to form said wall substantially normal to the plane in whichsaid backplate is rotatable.

3. A pulper impeller as defined in claim 1, wherein:

said wall, substantially normal to the plane in which said backplate isrotatable, is at least about 20% of the distance from the periphery ofsaid plate toward the center of said impeller.

4. A pulper impeller as specified in claim 1, wherein:

said inwardly facing Wall of each said vane is in a plane normal to aradial plane extending through the axis of rotation of said impeller.

5. A pulper impeller as specified in claim 1, plus a plurality ofattrition blades spaced around the periphery of said impeller, eachprojecting slightly beyond said periphery and at a predetermined anglefrom a radius of said impeller passing therethrough.

6. A circulating vane for use on the impeller of a pulper, said vanecomprising:

a body of predetermined length, having a base portion extending from thecentral portion of said impeller to the periphery thereof and ofgenerally arcuate configuration, said body having opposite, parallel,upstanding, side walls and having an outer face defined between theleading and trailing outer edges of said side walls;

said outer face shoping gradually upwardly and outwardly from the innerend of said body to a position centrally of the length thereof and thenturning abruptly and vertically outward to form an upstanding wallfacing the axis of said impeller and then turning parallel to said baseportion to proximate the periphery of said impeller.

References Cited UNITED STATES PATENTS 2,719,011 9/1955 Bebinger241-4611 3,017,125 1/1962 Sherman 241-4617 3,054,565 9/1962 Willems24146.11 3,085,756 4/1963 Danforth 24146.17 3,163,368 12/1964 Johnson241-4617 LESTER M. SWINGLE, Primary Examiner.

D. G. KELLY, Assistant Examiner.

1. A PULPER IMPELLER OF THE TYPE ROTATABLE BY A SHAFT WITHIN A TANK FORPULPING FIBROUS PAPER STOCK MATERIAL, SAID IMPELLER COMPRISING: ABACKPLATE, MOUNTED FAST ON SAID SHAFT AND HAVING A FLAT, DIAMETRICALFACE IN A SINGLE PLANE NORMAL TO THE AXIS OF SAID SHAFT, AND A PLURALITYOF PULPING CIRCULATION VANES, UNIFORMLY SPACED AROUND, AND PROJECTINGAXIALLY FROM, AND BACKPLATE, EACH SAID VANE BEING SUBSTANTIALLY ARCUATEIN PLAN, BEING OF PREDETERMINED LENGTH, AND BEING OF SUBSTANTIALLYUNIFORMLY INCREASING HEIGHT FROM A POSITION PROXIMATE THE CENTRALPORTION OF SAID BACKPLATE OUTWARDLY TO A FIRST POSITION CENTRALLY OF THELENGTH OF SAID VANE, SAID VANE INCREASING ABRUPTLY AND SUBSTANTIALLY INANGLE OF SLOPE FROM SAID FIRST POSITION CENTRALLY OF SAID LENGTH TO ASECOND POSITION CENTRALLY OF SAID LENGTH FOR FORM AN INWARDLY FACINGWALL SUBSTANTIALLY NORMAL TO THE PLANE OF SAID BACKPLATE AND PARALLEL TOTHE AXIS OF SIAD SHAFT, WHEREBY THE SAID INWARDLY FACING WALLS ON SAIDVANES FORM A ROTATING BARRIER TO OUTWARD VORTICAL FLOW FROM SAIDIMPELLER, THE RESULTING TURBULENT ZONE PREVENTING PLUGGING, MATTING, ANDSTAPLING OF MATERIAL ON SAID VANES.